A cardiac arrest is a life-threatening medical condition in which a person's heart fails to provide enough blood flow to support life. During a cardiac arrest, the electrical activity may be disorganized (ventricular fibrillation), too rapid (ventricular tachycardia), absent (asystole), or organized at a normal or slow heart rate (pulseless electrical activity). A person treating a cardiac arrest victim may apply a defibrillation pulse to the patient in ventricular fibrillation (VF) or ventricular tachycardia (VT) to stop the unsynchronized or rapid electrical activity and allow a perfusing rhythm to commence. External defibrillation, in particular, is provided by applying a strong electric pulse to the patient's heart through electrodes placed on the surface of the patient's body. The brief pulse of electrical current is provided to halt the fibrillation, giving the heart a chance to start beating with a more normal rhythm. If a patient lacks a detectable pulse but has an ECG rhythm of asystole or pulseless electrical activity (PEA), an appropriate therapy includes cardiopulmonary resuscitation (CPR), which causes some blood flow.
The probability of surviving a cardiac arrest depends on the speed with which appropriate medical care is provided to a patient experiencing the cardiac arrest. To decrease the time until appropriate medical care is provided, it has been recognized that those persons who are first to arrive at the scene, “first responders,” should be provided with an automated external defibrillator (AED). An AED that provides adequate instructions to the first responder improves the overall success rate of treating cardiac arrest patients. AEDs are generally designed for use by the first responder, who can be an emergency medical services worker, a firefighter or a police officer, or who can be a layperson with minimal or no AED training. The AED and the first responder work together to deliver resuscitative therapies to the cardiac arrest patient.
Typically, the AED is a small, portable device that analyzes the heart's rhythm and prompts a user to deliver treatment to the patient. Once the AED is activated, it can guide the first responder through each step of the treatment by providing audible and/or visual prompts, that may include CPR treatment and/or a defibrillation pulse, if it determines the desirability for such a pulse. Protocols have been developed for AEDs that typically provide instructions in time intervals, based on medical standards. These protocols generally call for CPR to be administered by the first responder in time intervals of a pre-programmed length, such as “do one minute of CPR”.
Unfortunately, under the pressures of an emergency situation, it can difficult for a first responder to accurately judge time intervals designated by the AED for CPR treatment. In addition, different first responders may differ in technique and may not consistently provide adequate CPR treatment during the time period designated by the AED.
Accordingly, it is desirable to provide a method and apparatus that quickly, accurately, and automatically prompts a first responder to provide CPR treatment or defibrillation, as appropriate, in an emergency situation. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.